Systems, Methods, and Media for Transcoding Video Data

ABSTRACT

Methods, systems, and computer readable media for transcoding video data based on metadata are provided. In some embodiments, methods for transcoding video data using metadata are provided, the methods comprising: receiving a first plurality of encoded images from a storage device; decoding the first plurality of encoded images based on a first coding scheme to generate a plurality of decoded images; receiving a plurality of encoding parameters from the storage device; and encoding the plurality of decoded images into a second plurality of encoded images based on a second coding scheme and the plurality of encoding parameters.

CROSS-REFERENCE TO RELATED APPLICATIONS

The current application is a continuation of U.S. patent applicationSer. No. 16/298,345 entitled, “Systems, Methods, and Media forTranscoding Video Data” to Naletov et al., filed Mar. 11, 2019, whichapplication is a continuation of U.S. patent application Ser. No.15/905,695 entitled, “Systems, Methods, and Media for Transcoding VideoData” to Naletov et al., filed Feb. 26, 2018 and issued on Apr. 16, 2019as U.S. Pat. No. 10,264,255, which application is a continuation of U.S.patent application Ser. No. 13/841,943, entitled “Systems, Methods, andMedia for Transcoding Video Data According to Encoding ParametersIndicated by Received Metadata” to Naletov et al., filed Mar. 15, 2013and issued on Feb. 27, 2018 as U.S. Pat. No. 9,906,785. The disclosuresof U.S. patent application Ser. Nos. 16/298,345, 15/905,695 and13/841,943 are hereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

Transcoding is an important task in video distribution applications. Forexample, a transcoder can receive input video data having a first formatand convert the input video data into video data having a second format.More particularly, for example, the first format and the second formatcan correspond to different video coding standards, such as Motion JPEG,JPEG 2000, MPEG-2, MPEG-4, H.263, H.264, AVC, High Efficiency VideoCoding (HEVC), etc. Alternatively or additionally, the first format andthe second format can have different bitrates and/or resolutions.

There are many current approaches to transcoding video data. Forexample, a transcoder can decode video data compressed in a first formatinto raw video data and re-encode the raw video data into a secondformat. More particularly, for example, the transcoder can estimateencoding parameters and re-encode the raw video data using the estimatedencoding parameters. The estimation of encoding parameters within atranscoder is very time-consuming.

Accordingly, new mechanisms for transcoding video data are desirable.

SUMMARY OF THE INVENTION

In view of the foregoing, systems, methods, and media for transcodingvideo data using metadata are provided.

In some embodiments, methods for transcoding video data using metadataare provided, the methods comprising: receiving a first plurality ofencoded images from a storage device; decoding the first plurality ofencoded images based on a first coding scheme to generate a plurality ofdecoded images; receiving a plurality of encoding parameters from thestorage device; and encoding the plurality of decoded images into asecond plurality of encoded images based on a second coding scheme andthe plurality of encoding parameters.

In some embodiments, systems for transcoding video data using metadataare provided, the systems comprising: processing circuitry configuredto: receive a first plurality of encoded images from a storage device;decode the first plurality of encoded images based on a first codingscheme to generate a plurality of decoded images; receive a plurality ofencoding parameters from the storage device; and encode the plurality ofdecoded images into a second plurality of encoded images based on asecond coding scheme and the plurality of encoding parameters.

In some embodiments, non-transitory media containing computer-executableinstructions that, when executed by a processing circuitry, cause theprocessing circuitry to performing a method for transcoding video dataare provided, the method comprising: receiving a first plurality ofencoded images from a storage device; decoding the first plurality ofencoded images based on a first coding scheme to generate a plurality ofdecoded images; receiving a plurality of encoding parameters from thestorage device; and encoding the plurality of decoded images into asecond plurality of encoded images based on a second coding scheme andthe plurality of encoding parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the invention will beapparent upon consideration of the following detailed description, takenin conjunction with the accompanying drawings, in which like referencecharacters refer to like parts throughout, and in which:

FIG. 1 shows a generalized block diagram of an example of anarchitecture of hardware that can be used in accordance with someembodiments of the invention;

FIG. 2 shows a block diagram of an example of storage device andtranscoder in accordance with some embodiments of the invention;

FIG. 3 shows a flow chart of an example of a process for transcodingvideo data in accordance with some embodiments of the invention;

FIG. 4 shows a flow chart of an example of a process for decoding videodata in accordance with some embodiments of the invention; and

FIG. 5 shows a flow chart of an example of a process for encoding videodata in accordance with some embodiments of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

This invention generally relates to mechanisms (which can be systems,methods, media, etc.) for transcoding video data based on metadata. Insome embodiments, the mechanisms can be used to transcode video datahaving a first format into video data having a second format.

In some embodiments, the mechanisms can receive a compressed bitstreamand media metadata. The mechanisms can decompress the compressedbitstream and generate decoded video data based on a first codingscheme. The mechanisms can then encode the decoded video data based on asecond coding scheme.

In some embodiments, the media metadata can include any suitable data.For example, the media metadata can include a set of coding parametersthat can be used to encoding video data. More particularly, the mediametadata can include information about one or more video scenes, such asa scene change indication signal, the number of frames between twoscenes, the type of a video scene, etc. The media metadata can alsoinclude motion data, intra-prediction information, picture complexityinformation, etc. about video data.

In some embodiments, the mechanisms can encode the decoded video datausing the media content data. For example, the mechanisms can generate aprediction image based on the motion data, the intra-predictioninformation, etc. As another example, the mechanisms can performrate-control on the decoded video data based on the information aboutthe video scenes, picture complexity information, etc.

Turning to FIG. 1, a generalized block diagram of an example 100 of anarchitecture of hardware that can be used in accordance with someembodiments is shown. As illustrated, architecture 100 can include amedia content source 102, a media encoder 104, a media metadata source106, a communications network 108, a storage device 110, a transcoder112, and communications paths 114, 116, 118, 120, 122, 124, 126, 128,and 130.

Media content source 102 can include any suitable device that canprovide media content. For example, media content source 102 can includeone or more suitable cameras that can be configured to capture stillimages or moving images. As another example, media content source 102can include one or more types of content distribution equipment fordistributing any suitable media content, including televisiondistribution facility equipment, cable system head-end equipment,satellite distribution facility equipment, programming source equipment(e.g., equipment of television broadcasters, such as NBC, ABC, HBO,etc.), intermediate distribution facility equipment, Internet providerequipment, on-demand media server equipment, and/or any other suitablemedia content provider equipment. NBC is a trademark owned by theNational Broadcasting Company, Inc., ABC is a trademark owned by theABC, INC., and HBO is a trademark owned by the Home Box Office, Inc.

Media content source 102 may be operated by the originator of content(e.g., a television broadcaster, a Webcast provider, etc.) or may beoperated by a party other than the originator of content (e.g., anon-demand content provider, an Internet provider of content of broadcastprograms for downloading, etc.).

Media content source 102 may be operated by cable providers, satelliteproviders, on-demand providers, Internet providers, providers ofover-the-top content, and/or any other suitable provider(s) of content.

Media content source 102 may include a remote media server used to storedifferent types of content (including video content selected by a user),in a location remote from any of the user equipment devices. Systems andmethods for remote storage of content, and providing remotely storedcontent to user equipment are discussed in greater detail in connectionwith Ellis et al., U.S. Pat. No. 7,761,892, issued Jul. 20, 2010, whichis hereby incorporated by reference herein in its entirety.

As referred to herein, the term “media content” or “content” should beunderstood to mean one or more electronically consumable media assets,such as television programs, pay-per-view programs, on-demand programs(e.g., as provided in video-on-demand (VOD) systems), Internet content(e.g., streaming content, downloadable content, Webcasts, etc.), movies,films, video clips, audio, audio books, and/or any other media ormultimedia and/or combination of the same. As referred to herein, theterm “multimedia” should be understood to mean media content thatutilizes at least two different content forms described above, forexample, text, audio, images, video, or interactivity content forms.Media content may be recorded, played, displayed or accessed by userequipment devices, but can also be part of a live performance. In someembodiments, media content can include over-the-top (OTT) content.Examples of OTT content providers include YOUTUBE, NETFLIX, and HULU,which provide audio and video via IP packets. Youtube is a trademarkowned by Google Inc., Netflix is a trademark owned by Netflix Inc., andHulu is a trademark owned by Hulu, LLC.

Media content can be provided from any suitable source in someembodiments. In some embodiments, media content can be electronicallydelivered to a user's location from a remote location. For example,media content, such as a Video-On-Demand movie, can be delivered to auser's home from a cable system server. As another example, mediacontent, such as a television program, can be delivered to a user's homefrom a streaming media provider over the Internet.

Media encoder 104 can include any suitable circuitry that is capable ofencoding media content. For example, media encoder 104 can include oneor more suitable video encoders, audio encoders, video decoders, audiodecoders, etc. More particularly, for example, media encoder 104 caninclude one or more video encoders that can encode video data includinga set of images in accordance with a suitable coding standard, such asMotion JPEG, JPEG 2000, MPEG-2, MPEG-4, H.263, H.264, AVC, HighEfficiency Video Coding (HEVC), etc. As referred to herein, an image canhave any suitable size and shape. For example, an image can be a frame,a field, or any suitable portion of a frame or a field, such as a slice,a block, a macroblock, a set of macroblocks, a coding tree unit (CTU), acoding tree block (CTB), etc.

Media metadata source 106 can include any suitable circuitry that iscapable of providing metadata for media content. The metadata for mediacontent can include any suitable information about the media content.For example, the metadata can include one or more coding parameters thatcan be used by suitable encoding circuitry and/or suitable decodingcircuitry to encode and/or decode video data including multiple videoframes.

In a more particular example, the metadata can include information aboutone or more video scenes, each of which can be composed of a set ofimages that have similar content. More particularly, for example, themetadata can include scene change information that can indicate thestart and/or end of one or more scene changes in the video data. In someembodiments, the metadata can also include a set of parameters that canindicate the type of each of the scene changes, such as a shot change, afading change, a dissolving change, etc. In some embodiments, themetadata can include the number of images between two scene changes. Forexample, the metadata can include the number of images between twoconsecutive scene changes, two scene changes of a given type (e.g., suchas two shot changes), etc.

In another more particular example, the media metadata can includepicture complexity information. The picture complexity information caninclude any suitable information about the spatial and/or temporalcomplexity of an image, such as a frame, a field, a slice, a macroblock,a sub-macroblock, a CTU, a CTB, etc.

In some embodiments, for example, the picture complexity information caninclude spatial complexity of an image that can indicate the amount ofintra-distortion across the image. The amount of intra-distortion can bemeasured in any suitable manner. For example, the amount ofintra-distortion of the image can be measured based on the variances ofpixel values, luminance, brightness, or other characteristics of theimage using a suitable metric, such as the mean absolute difference(MAD), the mean square error (MSE), etc. In some embodiments, thespatial complexity of a frame can be measured using the sum of thespatial complexity of the macroblocks and/or CTUs of the frame. In someembodiments, the picture complexity information can include a map ofspatial complexity distribution within a frame for each frame of thevideo data.

In some embodiments, for example, the picture complexity information caninclude temporal complexity of an image that can indicate the amount ofmotion between the image and one or more reference images. The amount ofmotion can be represented in any suitable manner. For example, theamount of motion between the image and a reference can be measured usinga suitable difference metric, such as the sum of the absolute difference(SAD), the sum of the squared difference (SSD), the mean absolutedifference (MAD), the sum of absolute transformed differences (SATD),etc. More particularly, for example, the temporal complexity of a framecan be represented as the SAD, SSD, MAD, SATD, etc. between twoconsecutive frames. In some embodiments, the picture complexityinformation can include a map of temporal complexity distribution withina frame for each frame of the video data.

In yet another more particular example, the metadata can include motiondata about the video data. The motion data can be generated in anysuitable manner and can include any suitable data about changes amongvideo frames due to object motions, camera motions, uncovered regions,lighting changes, etc. More particularly, for example, media metadatasource 106 can generate a motion vector map for each video frame of themedia content, motion characteristics (e.g., high motion, slow motion,etc.) of one or a set of frames, the number of B-frames between twoP-frames, etc. In some embodiments, the motion data can be generatedbased on a suitable motion estimation algorithm, such as a blockmatching algorithm, an optical flow algorithm, a sub-pixel motionestimation algorithm, a hierarchical block matching algorithm, etc. Forexample, in some embodiments, the motion vector map can include a set ofinteger vectors corresponding to each integer pixel of a video frame. Asanother example, the motion vector map can include a set of fractionalmotion vectors corresponding to each sub-pixel of the video frame (e.g.,½ pixel, ¼ pixel, ⅛ pixel, etc.). In some embodiments, the mediametadata can also include one or more reference lists that can contain aset of frames that can serve as reference frames.

As yet another example, the media metadata can include intra-predictiondata about the media content. The intra prediction data can include anysuitable data that can be used for intra prediction under a suitablecoding standard. For example, the intra-prediction data can include aset of candidate intra prediction modes, such as a vertical mode, ahorizontal mode, a DC mode, a diagonal down-left mode, a diagonaldown-right mode, a vertical-right mode, a horizontal-down node, avertical-left mode, a horizontal-up mode, a plane mode, an intra-angularmode, etc. Additionally, the intra-prediction data can include a codingcost and/or distortion corresponding to each intra-prediction mode.

In some embodiments, the media metadata can be stored based on the playorder of the video frames.

Storage device 110 can be any suitable digital storage mechanism in someembodiments. For example, storage 110 can include any device for storingelectronic data, program instructions, computer software, firmware,register values, etc., such as random-access memory, read-only memory,hard drives, optical drives, digital video disc (DVD) recorders, compactdisc (CD) recorders, BLU-RAY disc (BD) recorders, BLU-RAY 3D discrecorders, digital video recorders (DVR, sometimes called a personalvideo recorder, or PVR), solid state devices, quantum storage devices,gaming consoles, gaming media, or any other suitable fixed or removablestorage devices, and/or any combination of the same. Storage 110 may beused to store media content, media metadata, media guidance data,executable instructions (e.g., programs, software, scripts, etc.) forproviding an interactive media guidance application, and for any othersuitable functions, and/or any other suitable data or program code, inaccordance with some embodiments. Nonvolatile memory may also be used(e.g., to launch a boot-up routine and other instructions), in someembodiments. In some embodiments, storage 110 can store media content,encoded video data, and/or metadata provided by media content source102, media encoder 104, and/or media metadata source 106.

Transcoder 112 can include any suitable circuitry that is capable ofconverting input media content having a first format into media contenthaving a second format. For example, transcoder 112 can include asuitable video transcoder that can convert a first set of images thatare encoded in accordance with a first coding scheme into a second setof images that are encoded in accordance with a second coding scheme. Insome embodiments, the first coding scheme and the second coding schememay have different target bitrates. In some embodiments, the first setof encoded images and the second set of encoded images may havedifferent resolutions, such as spatial resolutions, temporalresolutions, quality resolutions, etc. In some embodiments, the firstcoding scheme and the second coding scheme may correspond to differentcoding standards, such as Motion JPEG, JPEG 2000, MPEG-2, MPEG-4/AVC,H.263, H.264, High Efficiency Video Coding (HEVC), etc. Moreparticularly, for example, in some embodiments, transcoder 112 canconvert a set of images encoded based on MPEG-2 standard into a set ofimages encoded based on HEVC standard.

In some embodiments, communications network 108 may be any one or morenetworks including the Internet, a mobile phone network, a mobile voice,a mobile data network (e.g., a 3G, 4G, or LTE network), a cable network,a satellite network, a public switched telephone network, a local areanetwork, a wide area network, a fiber-optic network, any other suitabletype of communications network, and/or any suitable combination ofcommunications networks.

In some embodiments, media content source 102, media encoder 104, mediametadata source 106, storage device 110, and transcoder 112 can beimplemented in any suitable hardware. For example, each of media contentsource 102, media encoder 104, media metadata source 106, storage 126,and transcoder 112 can be implemented in any of a general purpose devicesuch as a computer or a special purpose device such as a client, aserver, mobile terminal (e.g., mobile phone), etc. Any of these generalor special purpose devices can include any suitable components such as ahardware processor (which can be a microprocessor, digital signalprocessor, a controller, etc.).

In some embodiments, each of media content source 102, media encoder104, media metadata source 106, storage device 110, and transcoder 112can be implemented as a stand-alone device or integrated with othercomponents of architecture 100.

In some embodiments, media content source 102 can be connected to mediametadata source 106 through communications path 114. In someembodiments, media encoder 104 can be connected to media content source102 and media metadata source 106 through communications paths 116 and118, respectively. In some embodiments, communications network 108 canbe connected to media content source 102, media encoder 104, mediametadata source 106, storage device, and transcoder 112 throughcommunications paths 120, 122, 124, 126, and 128, respectively. In someembodiments, storage device 110 can be connected to transcoder 112through communications path 130.

Communications paths 116, 118, 120, 122, 124, 126, 128, and 130 mayseparately or together include one or more communications paths, suchas, a satellite path, a fiber-optic path, a cable path, a path thatsupports Internet communications (e.g., IPTV), free-space connections(e.g., for broadcast or other wireless signals), or any other suitablewired or wireless communications path or combination of such paths, insome embodiments.

Turning to FIG. 2, a block diagram of an example 200 of storage device110 and transcoder 112 of FIG. 1 in accordance with some embodiments ofthe disclosure is shown.

As illustrated, transcoder 112 may include a decoding circuitry 202, anencoding circuitry 204, a video-data storage 206, and communicationpaths 208, 210, 212, and 214.

Decoding circuitry 202 can include any suitable circuitry that iscapable of performing video decoding. For example, decoding circuitry202 can include one or more decoders that can decode a set of encodedimages based on a suitable coding standard, such as MPEG-2, MPEG-4, AVC,H.263, H.264, HEVC, etc.

Encoding circuitry 204 can include any suitable circuitry that iscapable of performing video encoding. For example, encoding circuitry204 can include one or more suitable encoders that can encode a set ofimages based on a suitable coding standard, such as MPEG-2, MPEG-4, AVC,H.263, H.264, HEVC, etc. In some embodiments, encoding circuitry 204 canalso include scaler circuitry for upconverting and/or downconvertingcontent into a preferred output format.

Decoding circuitry 202 can be connected to encoding circuitry 204through communication path 210. Encoding circuitry 204 can be connectedto video storage 206 through communication path 214. Transcoder 112 maybe connected to media storage 110 through communication paths 208 and212.

Each of decoding circuitry 202 and encoding circuitry 204 can includeany suitable processing circuitry. As referred to herein, processingcircuitry can be any suitable circuitry that includes one or moremicroprocessors, microcontrollers, digital signal processors,programmable logic devices, field-programmable gate arrays (FPGAs),application-specific integrated circuits (ASICs), hardware processors,etc., and may include a multi-core processor (e.g., dual-core,quad-core, hexa-core, or any suitable number of cores) or asupercomputer, in some embodiments. In some embodiments, processingcircuitry may be distributed across multiple separate processors orprocessing units, such as, for example, multiple of the same type ofprocessing units (e.g., two Intel Core i7 processors) or multipledifferent processors (e.g., an Intel Core i5 processor and an Intel Corei7 processor).

Video data storage 206 can be any suitable digital storage mechanism insome embodiments. For example, video data storage 206 can include anydevice for storing electronic data, program instructions, computersoftware, firmware, register values, etc., such as random-access memory,read-only memory, hard drives, optical drives, digital video disc (DVD)recorders, compact disc (CD) recorders, BLU-RAY disc (BD) recorders,BLU-RAY 3D disc recorders, digital video recorders (DVR, sometimescalled a personal video recorder, or PVR), solid state devices, quantumstorage devices, gaming consoles, gaming media, or any other suitablefixed or removable storage devices, and/or any combination of the same.Video data storage 206 may be used to store media content, mediaguidance data, executable instructions (e.g., programs, software,scripts, etc.) for providing an interactive media guidance application,and for any other suitable functions, and/or any other suitable data orprogram code, in accordance with some embodiments. Nonvolatile memorymay also be used (e.g., to launch a boot-up routine and otherinstructions), in some embodiments.

Each of storage device 110, decoding circuitry 202, encoding circuitry204, and video-data storage 206 can be provided as a stand-alone deviceor integrated with other components of architecture 200.

In some embodiments, storage device 110 can be connected to decodingcircuitry 202 and encoding circuitry 204 through path paths 208 and 210,respectively. In some embodiments, decoding circuitry 202 can beconnected to encoding circuitry 204 through communications path 212. Insome embodiments, encoding circuitry 204 can be connected to video-datastorage 206 through communications path 214.

Communications paths 208, 210, 212, and 214 may separately or togetherinclude one or more communications paths, such as, a satellite path, afiber-optic path, a cable path, a path that supports Internetcommunications (e.g., IPTV), free-space connections (e.g., for broadcastor other wireless signals), or any other suitable wired or wirelesscommunications path or combination of such paths, in some embodiments

In some embodiments, transcoder 112 can also include a demultiplexercircuitry (not shown in FIG. 2). The demultiplexer circuitry can be anysuitable circuitry that is capable of demultiplexing a media contenttransport stream (TS). For example, the demultiplexer circuitry canreceive a TS from storage 110 and demultiplex the TS into a videostream, an audio stream, program and system information protocol datastream, etc. The demultiplexer circuitry can also pass the video streamto decoding circuitry 202.

Turning to FIG. 3, a flow chart of an example 300 of a process fortranscoding video data in accordance with some embodiments of thedisclosure is shown. In some embodiments, process 300 can be implementedby transcoder 112 as illustrated in FIGS. 1 and 2.

As illustrated, process 300 can start by receiving a compressedbitstream at 302. The compressed bitstream can include any suitable dataand can be received in any suitable manner. For example, the compressedbitstream can include video data generated based on any suitable codingstandard, such as Motion JPEG, JPEG, MPEG-2, MPEG-4, H.263, H.264, HEVC,etc. More particularly, for example, the video data can include encodedimages, decoding parameters, header information, etc. In someembodiments, each of the encoded images can include one or morequantized transform coefficients.

In some embodiments, for example, the compressed bitstream can bereceived from storage 110 as illustrated in FIGS. 1 and 2. Alternativelyor additionally, the compressed bitstream can be received from mediaencoder 104 and/or media content source 102.

Next, at 304, transcoder 112 can decompress the compressed bitstream andgenerate decoded video data. The compressed bitstream can bedecompressed and the decoded video data can be generated in any suitablemanner. For example, transcoder 112 can decompress the compressedbitstream and generate multiple decoded images based on a suitablecoding standard, such as Motion JPEG, JPEG 2000, MPEG-2, MPEG-4, H.263,H.264, HEVC, etc. In some embodiments, the decoded images can have anysuitable color format, such as RGB, YCrCb, YUV, etc.

More particularly, for example, each of the decoded images can begenerated using a process 400 as illustrated in FIG. 4. In someembodiments, for example, process 400 can be implemented by decodingcircuitry 202 of transcoder 112 (FIG. 2).

As shown, at 402, decoding circuitry 202 can perform entropy decoding onthe compressed bitstream and extract the quantized transformcoefficients associated with each of the encoded images, decodingparameters (e.g., quantization parameters, coding modes, macroblockpartition information, motion vectors, reference lists, etc.), headerinformation, etc.

At 404, decoding circuitry 202 can perform inverse quantization on thequantized transformed coefficients associated with a current encodedimage to generate one or more transform coefficients. The inversequantization can be performed in any suitable manner. For example,decoding circuitry 202 can multiply each of the quantized transformcoefficients by a suitable quantization parameter. In some embodiments,for example, decoding circuitry 202 can obtain the quantizationparameter from the decoding parameters.

At 406, decoding circuitry 202 can perform an inverse transform on thetransform coefficients to generate a decoded residual image for thecurrent encoded image. The inverse transform can be performed in anysuitable manner. For example, the inverse transform can be an inverseDiscrete Cosine Transform (IDCT).

Next, at 408, decoding circuitry 202 can generate a prediction image forthe current encoded image. The prediction image can be calculated in anysuitable manner. For example, decoding circuitry 202 can generate theprediction image based on a suitable inter-prediction method byreferring to one or more previously decoded frames. More particularly,for example, decoding circuitry 202 can perform motion compensation onone or more previously decoded frames and produce a motion compensatedreference image as the prediction image. In a more particular example,decoding circuitry 202 can locate a previously decoded image or aportion of the previously decoded image as a reference image for thecurrent encoded image using a motion vector. The reference image canthen be used as the motion compensated prediction for the current image.In another more particular example, decoding circuitry 202 can locatetwo reference images for the current encoded image using one or moremotion vectors. Decoding circuitry 202 can then calculate a predictionimage for the current encoded image based on the reference images. Moreparticularly, for example, the prediction image can be a weightedprediction of the two reference images.

As another example, decoding circuitry 202 can generate the predictionimage based on a suitable intra-prediction method by referring to one ormore previously decoded pixels in the same frame. More particularly, forexample, decoding circuitry 202 can perform spatial extrapolation toproduce an intra-prediction image for the current encoded image. In someembodiments, one or more prediction images can be formed byextrapolating previously decoded pixels of the current frame in anysuitable direction, such as vertical, horizontal, diagonal down-left,diagonal down-right, vertical-left, horizontal-down, vertical right,horizontal-up, etc.

At 410, decoding circuitry 202 can generate a decoded image for thecurrent encoded image based on the residual image and the predictionimage. The decoded image can be generated in any suitable manner. Forexample, decoding circuitry 202 can add the prediction image to thedecoded residual image to produce the decoded image.

Turning back to FIG. 3, at 306, transcoder 112 can receive mediametadata. The media metadata can include any suitable data and can bereceived in any suitable manner. For example, the media metadata can bethe metadata produced by media metadata source 106, as described abovein connection with FIG. 1. More particularly, for example, the mediametadata can include information about video scenes (e.g., scene changeinformation, the number of the frames between scene changes, the type ofa scene change, the number of B-frames between two P-frames, picturecomplexity information, etc.), motion data about the media content(e.g., motion vector maps, reference lists, etc.), intra-prediction data(e.g., a set of candidate intra-prediction modes, the coding cost and/ordistortion corresponding to each candidate intra-prediction mode, etc.),etc.

In some embodiments, for example, encoding circuitry 204 (FIG. 2) canreceive the media metadata from storage 110. In some embodiments,encoding circuitry 204 can receive the media metadata from mediametadata source 106 through communications network 108 as illustrated inFIG. 1.

At 308, transcoder 112 can encode the decoded video data using the mediametadata based on a second coding scheme. The decoded video data can beencoded in any suitable manner. For example, transcoder 112 can encodethe decoded images into a set of encoded images based on any suitablecoding standard, such as MPEG-2, MPEG-4, H.263, H.264, HEVC, etc. Asanother example, transcoder 112 can encode the decoded video data into acompressed bitstream including a set of encoded images that has a givenbitrate. As yet another example, encoding circuitry 204 can encode thedecoded images into a set of encoded images that has a given resolution,such as a spatial resolution, a temporal resolution, a qualityresolution, etc.

More particularly, for example, transcoder 112 can generate each of theencoded images using a process 500 as illustrated in FIG. 5. In someembodiments, process 500 can be implemented by encoding circuitry 204 oftranscoder 112.

At 502, encoding circuitry 204 can receive the set of decoded images andthe media metadata. The set of decoded images and the media metadata canbe received in any suitable manner. For example, encoding circuitry 204can receive the set of decoded images from the decoding circuitry 202and receive the media metadata from storage device 110.

At 504, encoding circuitry 204 can divide a decoded image into one ormore suitable coding units based on the second coding scheme. Each ofthe coding units can have any suitable size and shape and can beobtained in any suitable manner. In some embodiments, for example, thesecond coding scheme can include the HEVC coding standard. Encodingcircuitry 204 can divide a video frame into multiple coding tree units(CTU), each of which can have a size of 8×8, 16×16, 32×32, 64×64, etc.In some embodiments, each of the CTUs can be partitioned into multiplecoding tree blocks (CTBs), each of which can have a size of 4×4, 8×8,16×16, etc. based on the size of the CTU. In some embodiments, each ofthe CTBs can be further partitioned into multiple coding blocks (CBs)and coding units (CUs).

At 506, encoding circuitry 204 can generate a prediction image for acoding unit. The prediction image can be generated in any suitable way.For example, encoding circuitry 204 can generate the prediction imagebased on the media metadata such as scene change information, motiondata, picture complexity information, intra-prediction information, etc.

In some embodiments, for example, encoding circuitry 204 can generatethe prediction image based on a suitable inter-prediction method byreferring to one or more reference images. More particularly, forexample, encoding circuitry 204 can calculate one or more suitablemotion vectors for the coding unit based on the motion vector mapcorresponding to the coding unit. Encoding circuitry 204 can thengenerate a motion compensated prediction image for the coding unit basedon the motion vectors by referring to one or more reference images. Insome embodiments, the motion compensated prediction image can begenerated based on one reference frame that can be located using thereference frame lists. For example, encoding circuitry 204 can locate aregion in the reference frame as a reference image for the coding unitbased on a motion vector. The reference image can then be used as aprediction image for the coding unit. In some embodiments, the motioncompensated prediction image can be generated based on two referenceframes that can be located using the reference frame lists. For example,encoding circuitry 204 can generate two reference images by locating aregion in each of the two reference frames, respectively, based on oneor more motion vectors. Encoding circuitry 204 can then produce aprediction for the coding unit using the two reference images. Moreparticularly, for example, the prediction for the coding unit can be aweighted prediction of the two reference images.

In some embodiments, encoding circuitry 204 can generate the predictedimage based on a suitable intra-prediction method. The intra-predictioncan be performed in any suitable manner. For example, encoding circuitry204 can generate an intra-prediction image for the coding unit based onthe media metadata, such as the intra-prediction data including the setof candidate intra-prediction modes, the coding cost and/or distortioncorresponding to each intra-prediction mode, etc. More particularly, forexample, encoding circuitry 204 can determine a sub-set of the candidateintra-prediction modes that can be used in accordance with the secondcoding scheme. Additionally, encoding circuitry 204 can select anintra-prediction mode from the sub-set of candidate intra-predictionmodes based on the coding costs and/or distortion corresponding to eachof the sub-set of candidate intra-prediction modes. Encoding circuitry204 can then generate a prediction image for the coding unit based onthe selected intra-prediction mode. More particularly, for example,encoding circuitry 204 can predict each pixel of the coding unit byextrapolating pixel samples in a direction defined by theintra-prediction mode.

At 508, encoding circuitry 204 can generate a residual image for thecoding unit. The residual image can be generated in any suitable manner.For example, the residual image can be generated at 506 by subtractingthe prediction image generated at from the original image of the codingunit.

At 510, encoding circuitry 204 can perform a transform on the residualimage and generate a set of transform coefficients. The set of transformcoefficients can be generated in any suitable manner. For example,encoding circuitry 204 can perform a Discrete Cosine Transform (DCT) onthe residual image and generate a set of DCT coefficients.

At 512, encoding circuitry 204 can perform quantization on the set oftransform coefficients. The quantization can be performed in anysuitable manner. For example, encoding circuitry 204 can determine asuitable quantization parameter (QP) for a coding unit based on a targetbitrate of the second coding scheme. Encoding circuitry 204 can thenquantize the transform coefficients using the QP. The target bitrate canbe any suitable bitrate, such as a constant bitrate, a variable bitrate,etc. A QP can be determined in any suitable manner. In some embodiments,for example, encoding circuitry 204 can reduce the bitrate of acompressed bitstream by increasing QP or increase the bitrate of acompressed bitstream by decreasing QP. In some embodiments, for example,an I-frame can be encoded using most bits, followed by a P-frame and aB-frame.

In some embodiments, encoding circuitry 204 can determine a QP based onthe media metadata (e.g., scene change information, the number of framesbetween two scenes, the type of each scene change, picture complexityinformation, etc.), the target bitrate in accordance with the secondcoding scheme, etc.

For example, encoding circuitry 204 can determine a QP for a group ofpictures (GOP) based on the media metadata. The QP can be determined forthe GOP in any suitable manner. More particularly, for example, encodingcircuitry 204 can determine the structure of a GOP (e.g., the length ofthe GOP, the distance between P-frames, the distance between I-frames,etc.) based on the media metadata and determine the QP for the GOP basedon the structure of the GOP.

In some embodiments, encoding circuitry 204 can calculate the number ofbits available to encode the GOP based on the structure of a GOP, theframe rate of the video data, the target rate, etc. Encoding circuitry204 can then calculate a QP for the GOP based on the number of bitsavailable to encode the GOP. More particularly, for example, the QP canbe calculated based on a suitable model that can define the relationbetween the QP and the target rate, such as a rate-distortion model, arate-distortion optimization model, etc.

In some embodiments, encoding circuitry 204 can determine the structureof GOP based on the media metadata, such as scene information, thenumber of frames between two scene changes, the number of B-framesbetween two P-frames, etc.

In a more particular example, the first frame of the GOP can be anI-frame that can be located using the scene change information. Moreparticularly, for example, the first frame of the GOP can correspond tothe start of a video scene.

In another more particular example, the length of the GOP, i.e., thenumber of frames in the GOP, can be determined based on the number offrames between two scene changes. In some embodiments, the length of theGOP can be equal to the number of frames between two adjacent scenechanges. In some embodiments, the length of the GOP can be equal to thenumber of frames between two given scene changes, e.g., two shotchanges, etc.

In yet another more particular example, the distance between P-frames inthe GOP can be determined based on the number of B-frames between twoP-frames included in the media metadata. In a more particular example,the GOP can include a set of frames IBBPBBP . . . where the distancebetween P-frames is three.

As another example, encoding circuitry 204 can determine a QP for thecoding unit based on the media metadata. More particularly, for example,encoding circuitry 204 can determine the complexity of the coding unitusing the picture complexity information (e.g., the maps of spatialcomplexity, the maps of motion complexity, etc.). Encoding circuitry 204can then calculate a target number of bits that are available to encodethe coding unit based on the complexity of the coding unit. In someembodiments, for example, more bits can be allocated to a coding unithaving relatively high complexity while fewer bits can be allocated to acoding unit having relatively lower complexity.

Additionally, encoding circuitry 204 can determine a QP for the codingunit to produce the target number of bits. More particularly, forexample, the QP can be calculated based on a suitable model that candefine the relation between the QP and the target rate, such as arate-distortion model, a rate-distortion optimization model, etc.

Next, at 514, encoding circuitry 204 can perform entropy encoding on thequantized transform coefficients. The entropy encoding can be performedin any suitable manner. For example, encoding circuitry 204 can performthe entropy encoding using a suitable variable length encoding method.

It should be noted that the above steps of the flow diagrams of FIGS.3-5 may be executed or performed in any order or sequence not limited tothe order and sequence shown and described in the figures. Furthermore,it should be noted, some of the above steps of the flow diagrams ofFIGS. 3-5 may be executed or performed substantially simultaneouslywhere appropriate or in parallel to reduce latency and processing times.And still furthermore, it should be noted, some of the above steps ofthe flow diagrams of FIGS. 3-5 may be omitted.

In some embodiments, any suitable computer readable media can be usedfor storing instructions for performing the mechanisms and/or processesdescribed herein. For example, in some embodiments, computer readablemedia can be transitory or non-transitory. For example, non-transitorycomputer readable media can include media such as magnetic media (suchas hard disks, floppy disks, etc.), optical media (such as compactdiscs, digital video discs, Blu-ray discs, etc.), semiconductor media(such as flash memory, electrically programmable read only memory(EPROM), electrically erasable programmable read only memory (EEPROM),etc.), any suitable media that is not fleeting or devoid of anysemblance of permanence during transmission, and/or any suitabletangible media. As another example, transitory computer readable mediacan include signals on networks, in wires, conductors, optical fibers,circuits, any suitable media that is fleeting and devoid of anysemblance of permanence during transmission, and/or any suitableintangible media.

The above described embodiments of the present disclosure are presentedfor purposes of illustration and not of limitation, and the presentdisclosure is limited only by the claims which follow.

What is claimed is:
 1. A method for transcoding video data, the methodcomprising: receiving a first plurality of encoded images from a storagedevice; decoding the first plurality of encoded images based on a firstcoding scheme to generate a plurality of decoded images; receiving aplurality encoding parameters from the storage device; and encoding theplurality of decoded images into a second plurality of encoded imagesbased on a second coding scheme and the plurality of encodingparameters.